Process of treating leather with coal-tar.



v UNITED STATES PATENT OFFICE.

LOFTUS HARLEY FRANCIS, OF PRINCETON, CALIFORNIA, 'ASSIGNOR OF ONE-FOURTH TO CHARLES L. DONOHOE AND ONE-FOURTH TO FRANK FREEMAN, OF WILLOW, CALIFORNIA.

PROCESS OF TREATING} LEATHER WITH COAL-TAR.

Patented Oct. 23, 1906.

Application filed May 8, 1906. Serial No. 315,832.

To all whom it may concern.-

ing Leather with Coal-Tar; and I do hereby to be a full, clear, and

declare the followin I the invention, such as exact description -0 will enable others skilled in the art to which it appertains to make and use the same.

This invention, which relates to the preservation of leather, contemplates an improved process of treating this material to obtain the complete saturation or im regnation thereof with coal-tar, whereby t e treated leather is Without impairment of strength and flexibility rendered absolutely vermin and water proof and its wear-resisting quality is greatly enhanced.

In practicing the im roved process I preparea bath of coal-tar liaving a temperature of approximately one hundred and ten (110) degrees Fahrenheit and immerse therein leather which has been tanned by the usual method and which may be in a split or unsplit condition and either before or after the rolling and glossing steps employed to fit the material as to weight or density, according to its intended use. The leather is kept immersed in the bath at the stated tempera- 4o'sure to express therefrom the superfluous,

ture for a period of time ranging from twenty- 'four (24) hours to six (6) days, dependent u on its density or thickness or the use for w ich it is intended, during which period it becomes thoroughly saturated or impregnated with the coal-tar. The saturated or impregnated leather is then removed from the bath and is passed between rollers exerting prescoal-tar and to force the retained coal-tar into all of the fibers. The rolled leather is then laced upon drying-racks or the like, and W en the moisture is nearly expelled it is a ain (passed between pressure-rollers and w en esired is glossed 1n the usual manner.

The products from diflerent coal-gas or coal-tar works usually vary in weight, and it is advisable in case of heavy tar to add a small quantit of gasolene' or the like to reduce the weig t and assist absorption, which, is accomplished by capillary actlon.

The absorbed coal-tar is thoroughly incorporated with the fibers of the leather, and in drying the leather becomes a compact guttapercha-like material having a high wear-resisting uality compared with leather which has not een so treated, Moreover, leather treated b this process retains its strength and flexibilit is antiseptic and verminproof, and wi 1 not become impaired by long ex osure to water.

claim' The herein-described process of treating leather with coal-tar, which consists in immersing the same for from one to six days in a bath of coal-tar having a temperature of ap roximately one hundred and ten degrees Fahrenheit, passing the tanned leather between pr'essure-rollers, abstracting by drying a portion of the moisture from the rolled leather, and again rolling the partly-dried leather.

In testimony whereof I aflix my signature in presence of two witnesses.

LOFTUS HARLEY FRANCIS. 

